Hierarchical routing query method of automatic switched optical network

1. A hierarchical route inquiry method in Automatic Switched Optical Network (ASON) used in a network comprising multi-layer route domains, comprising the following steps: (a1) A Route Controller (RC) of an ASON network element (NE) detects a Route Request launched by a requester, and then forwards the Route Request to a RC of a parent domain if the Route Request is a cross-domain Route Request; (a2) The RC of the parent domain calculates a route among all its child domains and sends an in-domain Route Request to the RC of each child domain on the route, the RC of each child domain calculates the route in its domain and returns a Route Response to the RC of the parent domain, after receiving the Route Response, the RC of the parent domain returns the route to the requester through the RC which launches the Route Request if the complete route can be obtained, otherwise a failure message is returned.

2. A method of claim 1 , wherein step (a2) further comprises the following steps: (a21) The RC of the parent domain calculates the route among its child domains, determines a boundary node of each child domain on the route, and then generates and broadcasts the in-domain Route Request including information of the boundary node corresponding to each domain to the child domains; (a22) After the child domains receive the in-domain Route Request, it calculates the route of its domain and returns the Route Response to the RC of the parent domain; (a23) After the RC of the parent domain receives the Route Responses from the child domains, it determines whether all of the Route Responses are successful, if yes, proceeding to the next step; otherwise, a failure message is returned to the requester through the RC which launches the request, ending; (a24) The RC of the parent domain combines the cross-domain route and the in-domain route of the child domains to generate the complete route between a starting node and an ending node, and returns the complete route to the requester through the RC which launches the Request, ending.

3. A method of claim 1 , wherein if the parent domain fails to calculate the cross-domain route in step (a1), the failure message is returned to the requester through the RC which launches the Request, ending.

4. A hierarchical route inquiry method in Automatic Switched Optical Network (ASON) used in a network comprising multi-layer route domains, comprising the following steps: (b1) After a Route Controller (RC) of a network element (NE) in ASON detects a Route Request sent by a requester, the RC of the NE in ASON calculates a route based on Route Data Base (RDB) of a current node, and returns a Route Response to the requester if a complete route is obtained, ending; otherwise, the Request is forwarded to a RC of the parent domain; (b2) The RC of the parent domain calculates the route based on the RDB of the current node according to the Request, and if the complete route is obtained, the complete route is returned to the requester through the RC which launches the Request, ending; otherwise, proceeding to the next step; (b3) The RC of the parent domain forwards the Route Request to the RCs of its other child domains, and receiving the Route Responses returned from the RCs of these child domains, if a complete route can be obtained, the complete route is returned to the requester through the RC which launches the Request; otherwise, the failure message is returned to the requester through the RC which launches the Request, ending.

5. A method of claim 4 , wherein step (b3) further comprises the following steps: (b31) The RC of the parent domain sends the Route Request to the RC of one child domain except for the one which launches the Request; (b32) After the RC of the child domain receives the Route Request, it calculates the route based on the RDB of the current node and returns the Route Response to the RC of the parent domain; (b33) The RC of the parent domain determines whether the Route Response returned from the RC of the child domain is the complete route, if yes, the route is returned to the requester through the RC which launches the Request, ending; otherwise proceeding to the next step; (b34) The RC of the parent domain determines whether there is a RC of another child domain that has not been queried, if there is, the Route Request is forwarded to the RC of this child domain, and turning to step (b32); otherwise, the failure message is returned to the requester through the RC which launches the request, ending.

6. A method of claim 4 , wherein step (b3) further comprises the following steps: (b31) The RC of the parent domain broadcasts the Route Request to the RCs of all other child domains except the one which launches the Request; (b32) After the RCs of all other child domains receive the Route Request, they calculate the route based on the RDBs of the current nodes and return the Route Responses to the RC of the parent domain; (b33) The RC of the parent domain determines whether there is the complete route in the Route Responses returned from the RCs of the child domains, if yes, the route is returned to the requester through the RC which launches the Request, ending; otherwise, the failure message is returned to the requester through the RC which launches the Request, ending.

7. A method of claim 1 , wherein when the RC of the parent domain sends the Route Request to the RC of the child domain, the Route Request is sent to the RC of a representative NE which represents the child domain to interact with an upper-layer route domain.

8. A method of claim 4 , wherein when the RC of the parent domain sends the Route Request to the RC of the child domain, the Route Request is sent to the RC of a representative NE which represents the child domain to interact with an upper-layer route domain.